Spark-plug.



M. P. SULLIVAN.

, SPARK PLUG.

APPLICATION FILED JULY 12, 1912.

1,163,281. Patented Dec.7,1915

A '3 1 we I 1T0 WWW was muuxlor/Y I) LAY) an UNITED STATES PATENT OFFICE.

MAURICE SULLIVAN, OF NEW YORK, N Y., ASSIGNOR TO L. F. BENTON COMPANY, A CORPORATION OF NEW YORK.

SPARK-PLUG.

-.Spe'cification of Letters Patent.

Patented Dec. 7, 1915.

To all whom it may concern 'Be it known that I, MAURICE P. SULLI- VAX,-2l citizen of the United States, and a resident of New York, county and State of New York, have invented a certain new and useful Improvement in Spark-Plugs, ofwhich the following is a full, clear, and

. exact specification.

This invention relates to a class of devices, or spark plugs adapted to, be used in the operation of combustion engines.

My invention has for its object primarily to provide a spark plug designed to be employed in connection with the compression chamber of a combustion engine for producing an electric spark whereby the charges of gaseous fuel admitted thereto may be eflectually exploded, and wherein is provided a form of electrode composed of a transmitting wire having one pole which'has pref erably a circular periphery and an arcshaped or semi-circular second pole which is arranged upon the casing of the plug in a position relative to the first pole whereby the area of the spark gap is greatly increased in comparison with the usual forms of electrodes, thus materially increasing the efficiency and durability of the plug byreason of the electric spark tending to follow panying drawing, which forms a part of this specification, and will be then pointed out in tlfe appendedclaim.

In the drawing, Figure 1 is an elevation, partlyin section and partly in detail, of one form of spark plug embodying my invention, and Fig. 2 is an inverted plan of the plug showing my improved form of electrode. 0

The device, or spark plug 10 has a casing 11 composed preferably of four superposed sections, as 12, 13, 14, 15, all of which may be made in any suitable size, and are tubular in formation whereby a continuous passage 16 is provided through said casing when the parts are assembled. In the passage 16 of the casing'll is a core 17 .which carries one of the poles of an electrode 18;

The tubular section 12 of the casing 11 has a lower exteriorly threaded portion 19 and a wrench-seat 20 wl be screwed in a threaded opening provided in any suitable part of the wall ofthe compression chamber of a combustion engine. The end of the section 12 which is opposite to the exterior-1y threaded portion-is interiorly threaded, at 22, for reception of the exteriorly threaded lower part of the tubular section 13 of said casing. Upon the upper end of the section 13 is a flange 23 which rests upon the end of the section 12 so as to produce a neat finish at the juncture of connection between. this section and said section 12. Upon the top of the flange 23 of the section 13 is a narrow collar21 in which is mounted one end of the tubular section let of the casing, and upon the opposite end of the section 151 is held the tubular section 15 which may be in the form ofa cap having the walls of its passage threaded, at 25. The sections 12, 13, and 15 are preferably made of metal to conduct currents of electricity, and the section 14 is preferably made of porcelain, or other non-conducting material. p

The core 17 consists of a. transmitting wire, or rod 26 the upper portion of which is threaded and engages the inner threads of the section, or cap 15 whereby said transmitting wire is rigidly held within the passage 16 of the casing. The threaded portion of the transmitting wire extends some distance above the cap 15, and screwed upon this extended part is a nut 27 which serves to connect the plug to the wire of the usual, or any preferred type of battery for charging the transmitting wire with an electric current. The transmitting wire, or rod 26 may be of any suitable-shape, but is preferably tapered, as shown, and upon its end opposite to the threaded portion thereof is a concentric flange 28. An msulating sleeve 29 of mica, or the like encircles the transmitting rod'26, and said sleeve is of a length so that its ends rest against the cap 15 and the flange 28 of said rod so as to properly insulate this rod from the sections 12 and 13 of the casing;

The electrode 18 consists of a pole 29 iereby the plug may 1 Y which is preferably'in the form of a round wire having one end mounted centrally in i the end of the transmitting rod 20, and said pole is of a length to extend through the lower opening of the casing of the plug. Upon the free end of the section 12 of the casing is a second pole 30 which is formed of twospaced projecting short arms 31 and 32-, each having one of its ends embedded in said-section, and the other ends of said arms are bridged by a transverse bar 33. The bar 33 is arc-shaped, or semi-circular, and is spaced from the pole 29 so that its terminals are in alinement with the axial center of-the pole 29. This relative position of the two poles of'the electrode thereby provides a spark gap of an unusually large area, and which serves to materially increase the efiiciency of the plug by reason of the electric spark tending to follow the radius of the arc-shaped or semi-circular pole as parts of it are reduced by being melted by the heat of the electric spark. I

In the foregoing description I have embodied the preferred form of my invention but I do not wish to be understood as limiting myself thereto, as I am aware that modifications may be made therein without dc parting from the principle, or sacrificing any of they advantages of this invention, therefore I reserve to myself the right to make such changes as fairly fall Within the scope thereof.

Having thus described my invention, I

claim as new and desire to secure by Letters Patent A spark plug comprising three superposed tubular sections and a means for holding said sections together, a core including a transmitting wire and an insulating covering therefor, said core having the body MAURICE P. SULLIVAN ll 'ithesses:

M. DERMoDY, QROBT. B. ABBOTT. 

